This application relates to oxygen flow control systems for emergency oxygen supply systems in passenger aircraft.
Emergency oxygen supply systems for passenger aircraft are well known and characterized by being able to provide to each passenger a supply of oxygen in the case of an emergency. These systems are designed to be used during cabin de-pressurization and thus are intended to supply each passenger with a sufficient oxygen flow to meet the physiological requirements for high-altitude survival.
In the past the main emphasis in development has been directed towards improved breathing apparatus, improved oxygen generation, or accurate delivery of oxygen to meet physiological requirements.
U.S. Pat. No. 6,244,540 issued to Stabile teaches a method for calculating the oxygen required after emergency cabin decompression, but is a relatively complex system that provides constant monitoring of altitude.
U.S. Pat. No. 5,709,204 issued to Lester discloses a specially designed escape mask, but does not recognize the problem of cabin depressurization and the need to charge the system quickly with oxygen using a pneumatic control system.
U.S. Pat. No. 5,809,999 issued to Lang teaches an emergency oxygen supply system of an aircraft equipped with a pressurized cabin, breathable gas is supplied by a gas generator (1) for generating an oxygen-enriched gas either from the ambient air, or from air tapped from the engine whereby passengers receive mixed gas having an adequate oxygen content. This system is complex and requires power during operation.
Therefore, what is needed in the art is an emergency oxygen supply system that is simple and responds to changes in altitude without external monitoring.
Further what is needed in the art is an emergency oxygen supply system that recognizes cabin depressurization and quickly charges the system with oxygen.
Even further what is needed in the art is an emergency oxygen supply system that doesn't require power to regulate oxygen flow after activation.